Mixing machine



Nov. 21, 1933. AfLAscH ET AL MIXING MACHINE Filed March 1, 1932 ALBERTLA 011 zR/vsr STJPOME/P Patented Nov. 21, 1933 J v v I UNITED STATES.PATENT- OFFICE I MIXING MACHINE Albert Lasch, Cannstatt, and ErnstStriimer, Stuttgart, Germany, assignors to Baker Perkins Company, Inc.,Saginaw, Mich., a corporation of New York Application March 1,1932,--Serial No. 596,132,

and in Germany March 7, 1931 i Claims. (Cl. 18-'2)' This inventionrelates to machines for mixing, fecting a speedy and thorough mixing,milling kneading, and plasticiz'ing tough materials such andplasticizing action. as rubber, and has for its object the provisionReferring to the drawing: of a novel rotor element having a mixing andFig. 1 is-an elevation in a plane parallel to that -5 stretching actionsuperior to that 'of the rotors of the axes of the rotors, showing tworotors 60'- used in previous machines and which in addiembodying thefeaturesof' my invention in their. tion effectively mills or grinds thematerial. In positions relative to each other in a mixing mathepreparation of homogeneous mixtures of rubchine.

ber, powdered chemicals, pigment, resin, re- Fig. 2 is a development ofthe surface of one claimed rubber etc. it is desirable that a milling ofthe rotors shown in Fig. 1. 5 '3 of the material be effectedto breakdown inde- Fig. 3 is a cross section of amixing machine pendentparticles and more thoroughly incorpotaken at right angles to the axesof the rotors rate the ingredients. 1 x shown in Fig; 1, near one end ofthe blades, and

Heretofore this desired milling action has been S OWS their Gil-Op e a pto the y- 1 attained to a small extent by increasing the end lindricalsurface and saddle of themixing ma--' 70' area of the blades orblade-carrying arms of the chine, which is of known form. rotor toprovide surfaces co-acting with the paral- Fig. 4 is a view similar toFig. 1 showing rolel adjacent end walls of the mixing trough. torshaving four blades and an alternative type The novel feature of ourinvention by which we of milling roll embodying the novelsprinciples, of

"attain the desired milling action is applicable to the invention. p 75any machine having two or more rotors,'prefer- Referring to Fig. 3, themixing trough 1 of ably driven at differential speed, each of whichknown form having two part-cylindrical 'porco-operates with at least oneof the other rotlons 2, 2 formin sad 3 a t eir t sec tors, and itconsists in providing one or more tion,has two rotors 4 each rotativelymounted- I milling rolls as a part of each rotor having coaxially withinone of the trough portions.2,-. 0 smooth or corrugated milling faces.These rolls Rotors 4 are coupled in known manner to a drivare circularin cross section and cylindrical or ing gear (not shown) which drivesthem opposite,- conical in form and each roll is closely spaced 1y toeach other, as indicated by the arrows.

I from the surface of the trough and from the cor- Preferably they aredriven at different speeds; responding roll of the co-operating rotor.but this is not necessary to obtain the advantages 5 Asecond'novelfeature of the invention conof the invention in theoperation of the masists in providing blades on the rotor having anchine; j l improved form" for effectively cutting the mate 'Referring toFig. 1, 'a pairof cylindrical rolls rial against thesaddle of the mixingtrough and 5 839 formed integral W1ch fl and e 1 for more effectivelykneading "the material, work--' of suitabledia Clifford t desiredmilling 90 ing it from side to side in the trough. We ac- Clearance fromh v 0f h trough d complish'this by'providing a plurality of bladesbetween the coropemting TOHS- Thfi-fi o on the rotor, the working edgeof at least one mining T0115 5 m be smooffih corrugated.- .blade formedto have two oppositely directed heliaccordmg to the kmd of mammal to beWorked- 40 cal sections joined to present an angle, such an- 4 shows iof the mining t" faces or rolls 10 or one belng frusto-conical 1n sg ini i liotazion g form and positioned with their smaller diameters 2? g iF ge 9 onelo er toward the ends of the rotor. Corresponding rolls a e mar y orme O an ang 8 11 on the co-operating rotor are oppositely facedtamed wlth respect to the dlrectmn of Totamon with their largerdiameters toward the ends of 106 of the rotor, so that each rotor has atleast one the rotor The taper of the rolls 9 and 10 is the blade whichwill Operate to spread the material same so that their milling surfacesare parallel toward its ends and at least one other blade which to eachother To employ this alternative form will gather the material from itsends toward its milling roll the trough and the saddle I Centertweentrough sections are appropriately formed to 10 5 A third feature of theinvention consists in the V onform to t hape of t rotors, As t ucombination of the novel milling surfaces with th lt rn tive, onemilling roll 5, or 11, may th imp v d blad s s t a by v tu their pebelocated near the middle of each rotor of a culiar shapes the blades workthe material alpair, with the blade. portions at the'ends of the p"ternately torand away from the milling rolls, ef-' milling surfaces.

The improved blade structure constituting the second feature of theinvention is shown in Figs. 1 and 2. Rotor 4 has three blades 6, 7, 8.At least one blade, 8, has its working edge bent to form two oppositelydirected straight or helical sections8a and 8b which join intermediatethe ends of the blade to present an angle 80. This angle is retardedwith respect to the direction of rotation of the rotor to operate togather the material from the ends of the trough toward the center. Atleast one of the other blades, for example blade 6, is similarly .bentto present an angle advanced in the direction of rotation of the rotorto spread the material from the center of the trough toward its ends.Blade 7 is shown bent to present an angle similar to that of blade 6,but may be straight or may have its angle facing in the oppositedirection.

Referring to Fig. 4, a rotor 10 or 11 may be built according to theinvention with four blades 12, 13, 14:, 15; of which blades 13 and 14present angles faced in one direction, blade 15 presents an angle facedin the opposite direction, and

blade 12 is straight. Any form of rotor having two or more blades may befashioned after this invention, so long as at least one blade presentsan angle faced in one direction and at least one blade presents anangle'faced in the opposite direction.

In the operation of the machine material is charged into the, trough 1and with rotors 4 oppositely driven at differential speeds, the materialis not only stretched and kneaded by the blades and sheared againstsaddle 3, but is also groundand rubbed between rolls 5 in a purelymilling operation. The material is also rubbed and spread against theend walls and curved surfacesof the part-cylindrical trough portions2.'by the rolls. Thus we obtain in one machine the operating advantagesof both the milling rolls and of the masticating blades, resulting in amore thorough and rapid'mixing of the material than can be accomplishedby ,a machine employing milling rolls alone or mixing blades alone.

The combination in one rotor of the milling rolls and the angularmaterial spreading and gathering blades, which effectively circulate thematerial between the milling surfaces, affords the greatest advantagesin operation and they are so describedand shown in the drawings.However, the milling rolls may advantageously be employed with the oldtype straight or helical blades, or the improved blades may be employedalone, and such independent use of either feature lies within the scopeof the invention as set forth in the claims.

Having thus described our invention, what we claim and desire to-secureby Letters Patent is:

1. A mixing machine comprising in combination a trough having twoparallel part-cylindrical sections, two parallel rotors, each rotativelymounted concentrically within one of said trough sections, each of saidrotors having two cylindrical milling rolls, one at each end, each ofsaid rolls having its end surface positioned in milling relation to theend wall of the trough and its cylindrical surface in milling relationto the part-cylindrical trough surface and to the cylindrical surface ofthe corresponding roll of the other'rotor, and a plurality of radiallyprojecting blades on each rotor extending between said milling rolls, atleast one of said blades having its working edge formed with twooppositely directed helical sections joined to present an angle, suchangle advanced in the direction of rotation of the rotor, and at leastone blade similarly formed to present an angle retarded with respect tothe direction of rotation of the rotor.

2. A rotor for a mixing machine .comprising two milling rolls one ateach end of the rotor, said rolls circular in cross section takenperpendicular to the rotor axis, and a plurality of blades extendingbetween said rolls, at least one of said blades having its working edgeformed with two oppositely directed substantially helical sectionsjoined to present an angle, such angle advanced in the direction ofrotation of the rotor, and at least one blade similarly formed topresent an angle retarded with respect to the directionof rotation ofthe rotor.

3. In a rotor for a mixing machine, a plurality of blades extendingsubstantially lengthwise of the rotor, at least one of said bladeshaving its working edge formed with two oppositely di-' rectedsubstantially helical sections joined to present an angle, such angleadvanced in the one blade similarly formed to present an angle.

retarded with respect to the direction of rotation of the rotor. 1

4. A rotor for a mixing machine comprising two milling rolls, one ateach end of the rotor, and a mixing blade extending between said rolls,and having a radius at no point greater than the maximum radius of saidmilling rolls.

5. In a mixing machine, a pair of rotors, each of said rotors having aplurality of mixing blades and a milling roll, said pair of rotorsmounted parallel to each other so that the roll and the blades of onerotor co-operate respectively with the roll and the blades of the otherrotor.

ALBERT LASCH.

ERNST sTRoMER.

